(a) Field of the Invention
The present invention relates to a silicon single crystal ingot and wafer, a growing apparatus and method thereof. More particularly, the present invention relates to a silicon single crystal ingot growing apparatus and method for controlling a flower phenomenon due to an abnormal process, and providing various oxygen concentrations corresponding to client's requirements (appropriate for semiconductor devices) uniformly in a longitudinal or radial direction, when the silicon single crystal ingot is grown based on a Czochralski method.
(b) Description of the Related Art
Generally, when the silicon single crystal ingot is grown based on a Czochralski method, it is necessary to uses a Si crucible for containing a silicon melt Such a silica crucible elutes oxygen, and the eluted oxygen reacts with the silicon melt and solutes in the same thereby being transited into SiOx As a result, the eluted oxygen is mixed into a single crystal Accordingly, it allows the single crystal to have a bulk micro defect (BMD) so that a wafer has an increased strength by the BMD acting as a gettering site with respect to a metal impurity in semiconductor manufacturing processes. However, it induces various defects and segregations thereby deteriorating a yield thereof on a production of a semiconductor device However, the oxygen concentration according to a longitudinal direction of the ingot is increased due to Oi(Interstitial Oxygen) pumping phenomenon, particularly, at a rear portion of the ingot. In addition, a rotation of the crucible along with a rotation of a seed (SR) induces a flower phenomenon (denoted because a surface of the crystal ingot look like a flower), which forms a radial cross section of the single crystal not as a circular shape, but as an indented shape. Regarding the flower phenomenon, yet, precise mechanism has not been discovered However, there are various theories related to the melt convection. In order to control such a crystal oxygen concentration and a flower phenomenon, the crucible and ingot rotation speed, ingot pulling speed, and the like have been controlled or a cooling heat history have been controlled by adjusting a heating area through a change of a hot zone (H/Z) design such as a length of a heater and physical properties of an insulating member. However, theses methods have problems in that they require a long time and involve a large cost for changing the H/Z design each time, and they also need a lot of time to establish new conditions because the ingot's quality such as oxygen concentration is changed according to the change of the H/Z. In addition, the most powerful method for controlling the flower phenomenon may include decreasing a pulling speed (hereinafter, referred to as P/S) and improving the rotation speed ratio of the seed and crucible However, theses methods also have a problem in that the productivity is deteriorated and a quality for satisfying such recent wafer quality requirements as a low defect density is not satisfied. The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art